Modern autonomous systems, such as autonomous vehicles, tend to be fitted with more and better sensors than in the past. Improved communications technology also means that more and better information can be relayed within the autonomous system and/or exchanged with a remote operator for the purpose of identifying or tracking targets.
Conventional systems for producing data describing target measurements depend on the ability of individual sensor platforms to cooperate together in groups and build an accurate local operational picture. The local pictures may then be fused in a higher level process to give a common operational picture from which information can be obtained.
However, attempts to connect groups of sensors and fuse their data have often encountered a common problem: that of poor alignment. The sensor platforms are subject to uncertainties regarding their location and orientation, both of the platform itself and of the sensors with respect to the platform; and their clocks are not in perfect synchronisation. These uncertainties lead to additional errors that, unless handled explicitly, can degrade the quality of the output from a conventional data fusion approach.
Solutions to the problem of alignment error have been proposed that extend the processes carried out in the data fusion centre, but they are subject to problems of practicality in present day and next generation systems as they are often more complex than conventional processes and, therefore, require prohibitively large amounts of processing. Furthermore, previously-proposed solutions require extra information to be communicated using on-board buses and off-board communications systems which currently have neither the capacity nor the message sets to provide such information. The quality of the solution can depend on the arrangement of targets within the field of interest, which is not usually controllable. Other known solutions require fixed targets or beacons, which are only available in certain environments and, once fixed, the platform to co-operator alignment error would gradually return over time when the sensor platform leaves the vicinity of the fixed targets or beacons.
Embodiments of the present invention are intended to address at least some of the problems outlined above.